WordReference Random House Unabridged Dictionary of American English © 2025
on•lap
(on′lap′, ôn′-),USA pronunciation n. [Geol.]
- Geologythe advance of a sea beyond its former shore.
- Geologythe layer or layers of sedimentary rock formed on a sea floor as a result of this advance. Cf. offlap.
- on + lap3 1945–50